Jack



Patented May 1%, i949 entree stares greater PATENT @FFEQE JACK Israel Goldberg, New York, N. Y. Application January 5, 1937, Serial No. 119,067 2 Claims. (Cl. 60-52) This invention relates to load-moving or loadlifting devices, generally known as jacks, and especially to a type wherein the load-engaging .means are automatically moved. to a loadengaging position prior to the amount of forcibly engaging the load to move it.

The principal object of this invention is to provide a device of this kind whereby the loadengaging member of such device is associated with means which hold the load-engaging member normally in a retracted position, so that when said means are released, the load-engaging member will move into its load-engaging position preparatory to the moment when force for the actual movement of the load is applied.

Another object of this invention is to provide a load-moving device of the hydraulic type wherein means are provided for keeping the loadengaging member normally in a retracted position, and where control means are connected with the device for instantaneously releasing the loadengaging member into a load-engaging position, or stopping'that load-engaging member at any intermediate desired position.

The foregoing and still other objects and important advantages will become more readily understood from the ensuing description and the accompanying drawing, which latter are held in a purely diagrammatical form for illustrating the principle of the device, and are therefore by no means intended to limit me to the specific construction shown, and wherein Fig. 1 illustratesmy device in a position prior to engaging a load, and

Fig. 2 illustrates the same device at a moment when its load-engaging member is released for contacting with the load.

Referring now specifica 1y to' the drawing, numeral I denotes a reservoir wherein a liquid medium is stored under pressure. Numerals ii and i2 indicate pump means which are preferably operated simultaneously by any suitable device, such as indicated at it. Numeral I 2 denotes a cylinder in which operates a piston 55 and from which extends a piston rod 5 through one end ll of the cylinder. At the outer end of piston rod it, there is preferably provided loadengaging means it, shown here in the form of a. V-shaped block. the shape of which, of course, may be varied. Between block it and the upper face of cylinder end ii, an expansion spring i9 is mounted which, when released, has the tendency of drawing piston rod it outwards and into engagement with the load to be lifted.

Reservoir i0, pump means it and i2, and cylinder i5 are all inter-connected by a system of conduits in which are located a plurality of check valves, manipulating valves and pressure control valves which permit the efficacious operation of the device and its automatic control at any desired position. From one end of reservoir 10 there issues conduit 20, which is connected by means of conduit 2i, through check valve 22, to

pump ll. duit 23, through check valve 2%, to conduit 25. and through it to the bottom head 26 of cylinder it. Conduit 25 connects through check valve Z'l From this pump leads another con- 2, is conduit 2s In this conduit is provided a hand-operated control valve 38. Conduit 3'! also connects with the bottom head 25 of cylinder it and is provided with another hand-operated control valve 39.

Check valves 22 and 29 of pumps ii and 92, respectively, may be considered intake valves. They operate only in one direction, permitting liquid to be drawn from reservoir it into cylinders ii and i2. Check valves 24 and ti areoutlet valves and permit liquid to enter, respectively, below and above piston l5, frompumps ii and i2,

when their pistons move toward their heads.

Check valves 21 and are again one-way valves and permit the passage of liquid from the reservoir, respectively, to below or above piston i5.

Pressure control valve 3% permits passage of liquid from above piston i5 into the reservoir" when the pressure in the cylinder becomes excessive. Control valve 38 governs the flow of liquid from the upper end of the cylinder, above the piston, while control valve 39 regulates the flow of liquid at the lower end of the cylinder, below piston l5.

, Operation The usual employment of jacks in lifting or.

otherwise moving loads consists generally in first,

moving the load-engaging member for some member, in this instance piston 66 with its end block i8, is normally held in the position shown in Fig. 1, that is, in opposition to compression of spring I9. This position is reached by closing valve' 38 and opening valve 39, and actuating" pumps H and i2. From Fig. 1 it will be clearly seen that pump l2 will supply liquid medium through upper head I'I, above piston I5, whereas pump II will supply the liquid medium through head 26, below piston I5, but inasmuch as valve 39 in conduit 31 is open, the liquid pumped by pump II is passed back into reservoir I0. When spring I9 reaches its completely or suiliciently compressed state and the upper portion of the cylinder cannot absorb anymore of the liquid pumped in by pump I 2, pressure regulating valve 36 will open and permit the excessive liquid to pass through conduit 33 by way of conduit 37 into reservoir I 0.

The position of the piston and rod I6 shown" in Fig. 1, is the normal position of the jack when not in use and when ready to be moved below the load to be engaged. The moment it reaches a desired place at which the load is to be lifted, valve 39 is closed and valve 38 is opened, as shown in Fig.2, whereby a free passage of the liquid is established between the upper portion of the cylinder and the reservoir.

Spring I9, being originally under compression, is released through this valve manipulation and automatically pulls up piston rod I6 into loadengaging position. The liquid above piston I passes through conduit 32, valve '38 and conduit 31, into the reservoir, and the liquid thus released from the cylinder enters through conduit 25 and check valve from the reservoir into the lower half of the cylinder below piston I5.

When block I8 forms contact. with-the load,

pumps I I and I2 are again actuated. Inasmuch as control valve 38 is open. any liquid ejected by pump I2 is passed through conduit 30, check valve 3|, into conduit 32, and through control valve 38 and conduit 31 to reservoir I0, whereas the liquid pumped by pump I I enters the cylinder below piston I5, and since the liquid thus entering cannot escape through closed control valve 39, piston I5 is pushed upwards, whereby the load is actually lifted by the jack.

When new the jack is to be released, valve 39 is opened and valve 38 is closed, at which moment the weight of the load will cause the downward movement of piston rod I6. At this moment the liquid below piston I5 can escape through open valve 39 into the reservoir, whereas liquid is drawn from the reservoir through conduit 34, and check valve 35, into the upper portion of the cylinder, as piston I5 moves downwards.

In order to bring spring I9 into its normally compressed position, pumps II and I2 are operated, whereby additional liquid is forced by pump I2 on top of the piston, whereas the liquid from below the piston is passed through conduit 31 and open valve. 39, into the reservoir. It is obvious. of course, that by closing valves 38 and 39 at the same time, piston I5 may be stopped at any desired position, whether under the load or free of the load.

In the drawing, I have illustrated a hydraulic jack. It is, of course, evident that similar results may be obtained by employing mechanical devices for compressing spring I9 and for releasing it, and I therefore shall not be limited to the application of an automatically operable load-engaging member to hydraulic jacks only. Furthermore, I have illustrated in the drawing a purely diagrammatical scheme of the conduit and valve arrangements, and have shown a jack for vertically lifting a load. It is obvious, however, that the jack may be placed horizontally or in any other desired position, and provided, instead of with block I8, with a suitable lever arrangement, such as is employed in service jacks for garages, wherein the entire jack arrangement is set on rollers and may be moved beneath a car.

By the same token, the arrangement of the conduit system may be changed and difierently located to meet specific requirements, since the drawing only serves for better understanding the broad principle 01 my invention.

I further wish to state that my device may be readily employed for moving loads other than those of automobiles and trucks, such as used in building construction or moving large objects. It is obvious, therefore, that the application of the principle of my invention may be applied to any power device for moving loads, and I*therefore reserve for myself the right to make changes and improvements and adapt my device to different applications as may be required, without departing from the broad scope of my invention, as set forth in the annexed claims.

I claim:

1. In a hydraulic jack, a cylinder, a piston therein, a piston rod extending from said cylinder and provided with load-engaging means, a spring interposed between said load-engaging means and said cylinder, hydraulic pump means and a reservoir, a system of valve-equipped con-- duits connecting said pump means and said reservoir with said cylinder, control valves for governing the flow of liquid above and below said pieton, a pressure regulating valve in said system, said spring being adapted to be kept normally under compression, when the control valve above said piston is closed and liquid is drawn from said reservoir and is injected by way of said pump means into the cylinder above the piston, said spring being further adapted to automatically elevate the load-engaging means into a load-engaging position when said control valve above the piston is opened, and to cause the outflow of liquid from above the piston to below the piston by way of said reservoir.

2. In a device for automatically engaging a load to be lifted, a hydraulic jack consisting of a cylinder, a piston operative therein, a piston rod projecting from the cylinder, 2. spring interposed between the outer end of the piston rod and said cylinder, a reservoir, pump means, a system of conduits connecting both ends of the cylinder, .the reservoir and said pump means, check valves in the conduits between said reservoir and said pump means permitting the movement of liquid from said reservoir to the pump means only, check valves in the conduits between the pump means and both ends of the cylinder, permitting the flow of liquid into the cylinder only, check valves in the conduits between the reservoir and both ends of the cylinder, permitting the flow of liquid into the latter only, a pressure regulating valve in a conduit connecting the upper cylinder end with the reservoir and permitting the flow of liquid from the cylinder into the reservoir at excessive pressure only, control valves for governing the flow of liquid at the upper and lower ends of the cylinder, said spring being adapted to be kept normally compressed when the upper control valve is closed and the upper end of the cylinder is filled with liquid, and to automatically elevate the piston rod to a load contacting position, when said upper control valve is opened and the liquid is urged by the action of the spring to pass from the upper cylinder end into its lower end via said reservoir.

ISRAEL GOLDBERG. 

